Hans and Zacharias Janssen of Holland in the 1590’s created the “first” compound microscope. Anthony van Leeuwenhoek and Robert Hooke made improvements by working on the lenses. Convex Lenses are curved glass used to make microscopes. The simplest optical microscope is the magnifying glass and is good to about ten times (10X) magnification. The compound microscope has two systems of lenses for greater magnification, (1) the ocular, or eyepiece lens that one looks into and (2) the objective lens, or the lens closest to the object.